Electronic data buffers are extensively used in today's computers, electronic instruments, and communication systems. As optical signals become more and more widely used in the transmission and processing of information, it is clear that converting optical signals to electrical signals for buffering is quite inefficient. Conventional data buffering utilizes electronic random access memory (RAM), which temporarily stores data for future use. In the optical domain, optical bistable devices such as bistable lasers, amplifiers, and self electrooptic devices (SEED's) have been proposed as optical stores. These optical bistable devices operate in a bit by bit fashion. However, the bit rate of these devices is limited to approximately a gigibit per second as described by H. F. Liu et al. in "Switching Characteristics and Maximum Repetitive Frequency of INGAASP/INP Bistable Injection Lasers", IEEE Journal of Quantum Electronics, Vol. 2E-24 January 1988, pages 43-51.
As an alternative, single mode optical fiber delay lines having a very low loss characteristic have been used as a temporary storage for optical data of a short fixed duration. These optical fiber delay lines operate in a fixed time duration with unlimited bit rates but have the restriction that the signal is attenuated due to the losses associated with the splitting, combining, and fiber loss.